Johnny Knoxville was born Philip John Clapp on 11 March 1971 in Knoxville, Tennessee.

Jackass TV's frontman, Knoxville, is one of the few people to have shocked Quentin Tarantino on screen. Asked by the BBC whether he ever found anything on screen 'gross', Tarantino replied:

"In my films? No, no, no. In other films yeah, I guess there's been some gross stuff. I was watching an episode of Jackass where Johnny Knoxville put some live leeches in his mouth and I started gagging. Aarrgh!"

Johnny Knoxville attended the American Academy of Dramatic Arts in California but dropped out after just two weeks. Instead he acted in some commercials and then started videotaping stunts for Big Brother Skateboarding magazine's skate videos.

In an interview of Johnny Knoxville by his friend, Chris Nieratko, who was the managing editor of Big Brother Skateboarding magazine, Johnny Knoxville described the impetus behind the stunts:

"I was watching the news one night, and it showed a guy getting pepper-sprayed. I thought it was pretty funny and I was like, "I should test the whole gamut of self-defense products on myself." I started by shooting myself. I was trying to get a 9 mm but I didn't know anyone who had one, so I had to borrow my neighbor's wife's gun, a .38. I didn't have much money at the time--actually, no money--but my mom gave me 300 bucks for Christmas, so I took that and bought the cheapest bulletproof vest I could find. I called the store and asked them, "Is this a good vest?" Oh, yeah," they said. "Top of the line." I'm like, "Here's what I'm going to do with it: I'm going to put it on and shoot myself with a .38." They said that they couldn't recommend my doing that--but I did. Once you commit, you've got to go and do it."

The videos of the stunts, which themselves enjoyed a select but appreciative audience, would become the basis for one of MTV's most successful shows, Jackass TV.

Although his risk-taking is partly a reaction to being very ill as a child, Knoxville has emphasised in interviews the influence of his father. Knoxville told the BBC:

"...I think it's more emulation of my father, and the movies and television shows that I grew up on. My father was always pulling pranks and stunts. My father would walk into a room and just take it over, and everyone would be laughing. I was like, "Wow!"

As well as appearing in Jackass: The Movie (2002), Jonny Knoxville has taken on various film parts. Initially the roles were fairly small, but Knoxville features much more prominently in recent work.

Johnny Knoxville also played Luke Duke, with Jessica Simpson playing Daisy Duke, in a film based on the television series The Dukes of Hazzard.

In The Ringer Johnny Knoxville played the main character, Steve, who enters the Special Olympics pretending to be developmentally disabled.

In September 2006 Jackass Number Two proved to be a great box office hit. Asked by Time magazine what his inspirations were, Johnny Knoxville replied: "We watched a lot of cartoons while writing Jackass 2, like Road Runner and Tom & Jerry ..."

Asked about weird moments, Knoxville said: "Steve-O and I were both in a llama suit ... we felt something pushing against us. I looked round and an elk had mounted us."

Johnny Knoxville was married to Melanie Clapp and they have a daughter, Madison, whose name is, reportedly, tattooed on Johnny's chest. However, in July 2007 Johnny Knoxville filed for divorce from his wife of 12 years citing irreconcilable differences.